SELECT Continent
,sum(Population)
FROM world.country
GROUP BY Continent;
library(DBI)
# 利用 `dbConnect()` 建立連線
con <- dbConnect(RMySQL::MySQL(),
dbname = "world",
host = "rsqltrain.ced04jhfjfgi.ap-northeast-1.rds.amazonaws.com",
port = 3306,
user = "trainstudent",
password = "csietrain")country <- dbReadTable(con, "country")
dbDisconnect(con)library(dplyr)
library(ggplot2)
query_df <- country %>%
group_by(Continent) %>%
summarise(ttl_pop = sum(as.numeric(Population))) %>%
arrange(ttl_pop)
query_df$Continent <- factor(query_df$Continent, levels = query_df$Continent)
bar_plot <- ggplot(query_df, aes(x = Continent, y = ttl_pop, fill = Continent)) +
geom_bar(stat = "identity", alpha = 0.5) +
xlab("") +
ylab("") +
theme_minimal() +
coord_flip() +
ggtitle("Population across continents")